3.3.7 Making a Back Up of In-Memory Database Data

The --exec-when-locked option of the
mysqlbackup command lets you specify a
command and arguments to run near the end of the backup, while
the database is still locked. This command can copy or create
additional files in the backup directory. For example, you can
use this option to back up MEMORY tables with
the mysqldump command, storing the output in
the backup directory. To delay any redirection or variable
substitution until the command is executed, enclose the entire
parameter value within single quotes.